WASHINGTON -- Gov. Bill Clinton is likely to make his first defining decision -- his choice for vice president -- early next week in a move to claim the national political stage a full week before his own nomination in New York on July 15. The decision will speak volumes about the Arkansas governor's view of the campaign ahead against President Bush and independent candidate Ross Perot.

Mr. Clinton's choice, if he has made one, remains a closely held secret and the topic of increasingly heated, if uninformed, speculation in the political community that centers on three candidates -- Rep. Lee H. Hamilton of Indiana and Sens. Al Gore of Tennessee and Harris Wofford of Pennsylvania. If there is a morning-line favorite among the political professionals, it is probably Mr. Hamilton.

The decision is viewed as a critical one for the Democratic candidate because it will be the first of serious import that he has made since hebegan his long campaign for the White House last year. The political importance of the choice is underlined by the fact Mr. Bush is still being criticized by political friends and foes alike for his decision four years ago to run with then-Sen. Dan Quayle of Indiana.

The political equation for Mr. Clinton has two principal elements. He has made it clear all along that he would want a running mate who could fill in some of the blanks in his own official resume -- suggesting a Washington figure with foreign policy credentials, a description that applies to Mr. Hamilton and Mr. Gore, as well as several others who have figured in the speculation.

The second obvious goal would be to gain at least a marginal advantage in competing for the electoral votes of a large state. Mr. Wofford's Pennsylvania has 23 electoral votes, the fifth largest after California (54), New York (33), Texas (32) and Florida (25). But, as Michael S. Dukakis discovered with Sen. Lloyd Bentsen of Texas, vice-presidential nominees cannot always deliver their states.

The plan to announce the selection before the convention is intended to allow Mr. Clinton to dominate the news the week before as well asthe week of the Democratic convention. "It would give him two bites out of the apple," said Paul Tully, political director of the Democratic National Committee.

An early decision would also allow the logistical planning for the vice-presidential nominee to be carried out earlier so the campaign could begin in earnest immediately after the convention. One of the lessons the Democrats learned from their unhappy experience with Mr. Dukakis in 1988 is that "down time" not a luxury they can afford, particularly when they are &L competing not only with the White House but with Mr. Perot for the attention of the press and the electorate.

Finally, a pre-convention decision would forestall any movements New York for other candidates that could be difficult to stifle without causing embarrassment and hard feeling.

The supposed short list does not include several prominent Democrats who might, in fact, be on it, including Sens. Bob Kerrey of Nebraska, Bob Graham of Florida, John Kerry of Massachusetts and John D. "Jay" Rockefeller IV of West Virginia. At least two prominent possibilities, Gov. Mario M. Cuomo of New York and Sen. Bill Bradley of New Jersey, have taken themselves out of the picture.

Mr. Hamilton, 61, represents a state with only 12 electoral votes and a history of voting heavily Republican in presidential elections. But Mr. Hamilton, who is in line to become chairman of the House Foreign Affairs Committee, is a highly respected legislator with a reputation for probity and intelligence. He is also old-shoe enough in his personal style to be immune to the charges of slickness that have plagued Mr. Clinton.

Mr. Gore, 44, also has strong for eign policy and national defense credentials as well as a reputation for expertise on the environment. But Tennessee casts only 11 electoral votes, and it is far from clear why Mr. Clinton might think he would need another Southern moderate from a state abutting his own. Mr. Gore does have the advantage of having run for the nomination four years ago and understanding the pressures on a national candidate.

Mr. Wofford, a tweedy 66-year-old former college president, won an upset in a special election last year but has relatively little political experience. And, although he describes himself as a supporter of abortion rights, he backed the Pennsylvania law putting restrictions on abortion, which could make him a hard sell with abortion-rights activists.

Mr. Kerrey, 48, was one of the early favorites in the speculation because his history as a Vietnam war hero offered such a sharp contrast with Mr. Quayle. But the relationship between Mr. Clinton and Mr. Kerrey has been prickly at times, and some Democratic strategists have concluded that any of their candidates will match up favorably against the incumbent.